Ornithine transcarbamylase deficiency that developed at the age of 19 years with acute brain edema.

A 19-year-old man had nausea, diarrhea, and general malaise the day before requesting emergency transport to his former primary physician. The patient became restless and had tonic seizures after admission. The patient was transferred to our hospital as there had been no improvement in his level of consciousness. On arrival, cranial computed tomography showed generalized swelling, and blood ammonia concentration was ≥500 μg/dL. After admission, seizures recurred continually despite careful monitoring and increased doses of sedatives and antiseizure drugs. Dilated pupils and a flat electroencephalogram were evident on day 4 of admission, and the patient died on day 11. Ornithine transcarbamylase deficiency was diagnosed at postmortem based on fractionation of blood and urine amino acids and orotic acid.

Urea cycle disorders need to be treated urgently to prevent irreversible neurological damage when accompanied by hyperammonemia.

In cases of hyperammonemia, early dialysis should be considered to reduce the ammonia level.